<!DOCTYPE html>
<html lang="zh_CN">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

</body>
<script type="text/javascript">

    function sum(a, b) {

        return '返回一个值';


        console.log(a + b); // rerun后面的代码不会执行 没有意义

    }


    var a = 12;
    var b = 24;

    var c = 12;


    console.log(sum(a, b)); // 1. 直接打印函数的返回值
    var rs = sum(a, b); // 2. 返回值交给rs变量
    console.log(rs);


</script>

</html>
